1. Field
Aspects herein relate to devices and systems cooperating with shunt systems to flush occlusions in or near shunt catheters and in particular to devices and systems cooperating with shunts used to treat hydrocephalus.
2. Discussion of Related Art
Hydrocephalus is a condition in which cerebrospinal fluid (CSF) is unable to drain through natural mechanisms and instead accumulates in the ventricles of the brain. Conventional treatment of hydrocephalus includes the use of a shunt catheter or other drain tube having a proximal end inserted into the ventricle(s) and the opposite, distal end of the tube emptying into the abdominal cavity. The proximal end of the catheter includes one or more pores through which the CSF can enter and flow to the abdominal cavity. A one-way check valve is often included in the line, typically closer to the proximal end of the shunt. The valve acts to maintain the proper pressure in the ventricles, yet allow drainage of CSF to the abdominal cavity.
Shunt obstruction can occur at any time after insertion, and all points along the shunt course are suspect when assessing for shunt malfunction. Shunt obstruction usually presents with clinical evidence of raised intracranial pressure. The presentation is age-dependent, with infants usually having nausea, vomiting, irritability, and a bulging fontanel. Older children and adults usually present with headache, nausea, vomiting, cranial nerve palsies, and ataxia among other neurologic findings.
The most common location for obstruction is the ventricular catheter tip, which can be blocked by ingrowth of choroid plexus. Currently, this kind of obstruction of a shunt is only managed by surgical revision. Revision typically begins by opening the cranial incision to assess the outflow from the ventricular catheter. When the ventricular catheter is obstructed, cerebrospinal fluid flow is diminished or absent completely. Obstruction isolated to the ventricular catheter with adequate distal flow is treated by removal and replacement with a new catheter with similar specifications for length and diameter. Commonly, the ventricular catheter is obstructed by ingrowth of choroid plexus into the lumen of the ventricular catheter tip. Removal in this circumstance is complicated by the risk of bleeding caused by avulsion of choroid plexus if the catheter is forcefully removed.
Some of the existing shunt systems allow back flushing, a process that uses the CSF present in the shunt system to remove the obstructing matter.